Description:
Compilation of macros with ACLiC is broken. When adding "+" to the macro name, I get the following error:

Processing test.C+...
Info in <TUnixSystem::ACLiC>: creating shared library /home/sturchikhin/temp/./test_C.so
In file included from /usr/include/c++/9.2.0/ext/string_conversions.h:41,
from /usr/include/c++/9.2.0/bits/basic_string.h:6493,
from /usr/include/c++/9.2.0/string:55,
from /usr/include/TSchemaHelper.h:17,
from /usr/include/TGenericClassInfo.h:16,
from /usr/include/Rtypes.h:193,
from /usr/include/TObject.h:17,
from /usr/include/TNamed.h:25,
from /usr/include/TDictionary.h:44,
from /usr/include/TClass.h:23,
from /home/sturchikhin/temp/test_C_ACLiC_dict.cxx:14:
/usr/include/c++/9.2.0/cstdlib:75:15: fatal error: stdlib.h: No such file or directory
75 | #include_next <stdlib.h>
| ^~~~~~~~~~
compilation terminated.


This works fine if I install root-6.18.04-4 and broken since 6.18.04-5, so it may be caused by https://git.archlinux.org/svntogit/community.git/commit/trunk?h=packages/root&id=bc46e309dde2e934e20736e2a67d51e468ae71d9.

Additional info:
* package version: 6.18.04-8, was working in 6.18.04-4, broken since 6.18.04-5; gcc version is gcc-9.2.0-4.

Steps to reproduce:
* Create any simple macro test.C, like "void test() {}"
* run it with compilation, "root -l -n -q test.C+"